From that account, it looks like the key break was likely that the first alias to promote Silk Road (altoid) was at one later point also linked to a real-name gmail address (rossulbrecht@gmail).
Even if that association was brief, plenty of people (and even law enforcement researchers) are likely scraping/archiving or email-subscribed to the bitcoin forum where the association appeared. The same goes for 'tor' forums or tags elsewhere... so an actual law-enforcement approach to StackOverflow/Bitcointalk/Gmail/etc may not have even been necessary.
(OTOH, Bitcointalk.org is currently down after an attack that may have resulted in the leak of username/hashed-password/email records. User altoid's email address there could have been obtained by law enforcement, by subpoena or hack, and also pointed towards Ulbrecht.)
http://arstechnica.com/security/2013/10/silk-road-mastermind...
From that account, it looks like the key break was likely that the first alias to promote Silk Road (altoid) was at one later point also linked to a real-name gmail address (rossulbrecht@gmail).
Even if that association was brief, plenty of people (and even law enforcement researchers) are likely scraping/archiving or email-subscribed to the bitcoin forum where the association appeared. The same goes for 'tor' forums or tags elsewhere... so an actual law-enforcement approach to StackOverflow/Bitcointalk/Gmail/etc may not have even been necessary.
(OTOH, Bitcointalk.org is currently down after an attack that may have resulted in the leak of username/hashed-password/email records. User altoid's email address there could have been obtained by law enforcement, by subpoena or hack, and also pointed towards Ulbrecht.)